There is already known from WO 2008/058910 A1 a protective hood rotation prevention device of a power tool, in particular of an angle grinder, which has a clamping unit provided for clamping a protective hood unit and having a clamping element, a rotation prevention unit having a rotation prevention element, and which comprises a movement coupling unit, which is provided to move the rotation prevention element, in dependence on a movement of the clamping element, in an operating state.